elf: Make dl-rseq-symbols Linux only

And avoid a Hurd build failures.

Checked on x86_64-linux-gnu.

elf/Makefile

@@ -73,7 +73,6 @@ dl-routines = \
   dl-origin \
   dl-printf \
   dl-reloc \
-  dl-rseq-symbols \
   dl-runtime \
   dl-scope \
   dl-setup_hash \

sysdeps/unix/sysv/linux/Makefile

@@ -616,6 +616,10 @@ tests += \
 endif
 
 ifeq ($(subdir),elf)
+dl-routines += \
+  dl-rseq-symbols \
+  # dl-routines
+
 sysdep-rtld-routines += \
   dl-brk \
   dl-getcwd \